Very cool game! I like the visuals and the style. Making the player split their attention is a difficult mechanic to pull off - especially in a boss rush, where the player doesn't get much practice with the controls. I think you pulled it off, though. I found myself playing it like a sort of rhythm game.
I couldn't make it past the second boss, though. The first phase has this really fast dash attack that hit me every single time - I couldn't tell when it was coming, and it was too fast to avoid. Then, in the second phase, I felt like the axe following me around put me in some unfair positions, where I couldn't dodge the axe, the boss, and the boss's flying fist attack all at once.
That said, though, this is one of my favorites of the jam so far. Great job!